"My dispute is over the game map, not the mechanics and overall style, which is identical to the world I had created for MonsterUp Adventures," Sounas told Joystiq. The blog compares the two games' monsters and overworlds, each being an island with markedly similar features such as trees, hills and shadows. Sounas began uploading his creations for the game to the Dribbble design community site in April 2012 as well as the Behance portfolio site in July 2012. Sounas said he contacted both SleepNinja and publisher Cartoon Network regarding the allegations and "their replies are pending." Likewise, Cartoon Network replied to an inquiry from Joystiq, noting the publisher is "looking into this" and "will be in touch with a response."

"I had uploaded to my promotional sites the map, so it was very easy for a young designer to get inspiration by my artwork, something which is not bad," Sounas said. "But ripping off a map is a totally different thing." The designer said he would have "no problem" if SleepNinja removed its game map and inserted "something original" in its place. "I wouldn't bother if this was just a Chinese copy, but this company is from USA and they have no design ethos. It's unacceptable," Sounas added.

MonsterUp Adventures is a Doodle Jump-style game in which players guide their bouncing monster-like characters upward, collecting items along the way, a style of gameplay entirely different from that of Monsters Ate My Birthday Cake. MonsterUp Adventures is available on iOS, Android and Windows Phone. "Many people have been inspired by my artwork during the last years but they usually respect me and give credits," Sounas added, pointing to Fluttermind's Incoboto, a game that received a postmortem discussion from its developer that pointed to Sounas' "Space Alone" animation as inspiration.

Update: We've added the full infographic of comparisons between the two games below, provided by Sounas. You can view a larger version on Sounas' website here.